Seismic moment summation for historical earthquakes in Italy - tectonic implications
- Durham Univ. (United Kingdom)
Tectonic deformation rates in and around the Apennine mountains of Italy are studied using seismic moments estimated from macroseismic effects of historical earthquakes. Northeastward extension in the northern Apennines (north of about 42.5 deg N) accompanies shortening along their northeast flank. Since the seventeenth century, the sparce seismicity in these two zones has included no earthquake with magnitude greater than 6.5 or seismic moment above about 6x10 exp 18 N m. Their spatially averaged deformation rates are only about 0.3 mm/yr, but are equal, such that the extention and shortening balance with no relative motion between their external surroundings. In contrast, the numerous historical earthquakes in the central and southern Apennines with magnitude about 7 and seismic moment about 20x10 exp 18 N m require northeastward relative velocity across the deforming zone up to about 5 mm/yr, matching the expected relative motion of their surroundings. The northern Apennines thus show different senses and rates of deformation from localities farther south, and are thus tectonically distinct at present, in contrast with previous interpretations. 82 refs.
- OSTI ID:
- 7183973
- Journal Information:
- Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97; ISSN JGREA2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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540210* -- Environment
Terrestrial-- Basic Studies-- (1990-)
58 GEOSCIENCES
580000 -- Geosciences
DEFORMATION
DEVELOPED COUNTRIES
EARTHQUAKES
EUROPE
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
HISTORICAL ASPECTS
ITALY
PLATE TECTONICS
SEISMIC EVENTS
SEISMOLOGY
TECTONICS